"We give them a tasting here," said Steve Roser, vice president of Elbit Systems of America, who was hawking drones this week at the annual Border Security Expo, a high-tech bazaar aimed at those who police the criminal shadow lands along international frontiers. "We get them a little interested."

U.S. Customs and Border Protection last year spent more than $300 million for border security, fencing infrastructure and technology, and has requested appropriations totaling nearly $400 million for 2015.

But the border bonanza may only be beginning. An immigration reform plan debated in Congress last year called for raising the ante by several orders of magnitude, spending as much as $46 billion on heightened border security, including $3.2 billion on sophisticated surveillance equipment.

The legislation stalled, but that hasn't stopped the growth of the gadget-heavy industry on display here at what is billed as the largest exhibit of border security equipment in the world.

Attendees from 14 nations surveyed gizmos from nearly 100 manufacturers aimed at "disrupting and dismantling transnational criminal organizations" — and tapping into what is seen as an increasingly lucrative U.S. market.

With worldwide demand rising for security products, "there's more development in this field for devices that help people protect themselves," said Enrique H. Herrera Martinez, chief executive of TPS Global, which develops armored vehicles.

Men and women in suits and law enforcement uniforms milled around a convention hall during the two-day conference that ended Wednesday, ogling hundreds of high-tech instruments designed to detect humans — be they drug smugglers, immigrants or others — making their way into a country.

Gregory Schultz, who co-owns a Tucson-based business that manufactures clothing that stops electricity from penetrating a body, said his product, Thorshield, could help save border agents at risk of having their stun guns seized by assailants and used against them.

Schultz covered his hand in the cotton-like material, took up a stun gun and fired repeatedly.

"It's a highly conductive fabric that actually short-circuits stun guns and Tasers," he said without blinking.

Roser said his company's drones were in use along the Afghan and Israeli borders.

The unmanned aerial vehicle, which has a camera able to move any which way, is compact enough to carry in a backpack. It's light enough to launch by hand and can soar up to 3,000 feet.

Roser said expos such as the one in Phoenix were crucial, giving him the opportunity to meet the movers, shakers and purse-string holders in high levels of the federal government.

Matthew C. Allen, a special agent with U.S. Immigration and Customs Enforcement, said government must improve its technological expertise because criminals were doing the same thing. "We have adaptable adversaries," he said.

But this festival of peddling and purchasing comes at a time when President Obama and congressional Republicans are at odds about a budget and already are ordering a $500-billion cut to defense spending over the next decade.

And it's exactly these types of surveillance gadgets that worry people like Chris Rickerd, policy counsel for the American Civil Liberties Union, who wonders whether criminals will be the only ones in these high-tech surveillance sights.

"It's creating a warlike setting. There is a real question of fiscal responsibility, but also quality of life in border communities," he said. "There's not enough oversight."

Rickerd said there needs to be a thorough evaluation of whether the technology now in place is working before purchasing more gadgets.

He pointed to the Secure Border Initiative Network, a $1-billion system with a high error rate that ended up covering only a 53-mile stretch of the Arizona-Mexico border with high-tech cameras, radar and vibration sensors.

In 2011, officials replaced it with the Arizona Border Surveillance Technology Plan, a $700-million high-tech effort to boost border security. The Government Accountability Office in a report this month found that the effort had no evaluation system, so there's no way to show whether new camera towers or motion sensors have helped Border Patrol agents.

"Rolling out projects like that is really concerning," Rickerd said. "It's a waste of money."

Still, there was no shortage at this week's expo of opportunities for spending money.

Kurt Ludwigsen held a faux tree stump in one hand and a fake small cactus in the other. These polyurethane concealments, some as tall as 7 feet, can be used for different purposes but mainly are designed to house spy cameras that can be wired to another location or send data to a smartphone.

"Specifically for the border what you're looking to do is … drop these every thousand yards all along the way and have that digital feed come back to you," Ludwigsen said.

Perhaps the most eye-catching exhibit was a bullet-riddled 2008 Jeep Grand Cherokee that used to belong to Minerva Bautista Gomez, security chief for the Mexican state of Michoacan. Drug cartel members attacked the SUV in 2010 with guns and grenades.

"It took 14 minutes of nonstop fire," said Patricio Canavati, manager of operations in Texas for TPS Global. There were 2,700 bullet shells found at the scene, Canavati said. "Thank God she walked away with only minor scratches and bruises."

The company, which is headquartered in Mexico, opened its first U.S. office about a year ago, Herrera Martinez said.